[HTC One A9] jmanley69:
Here's my output from the commands I listed in the first post... You should get something similar if things went well.

C:\android>[B]fastboot oem rebootRUU[/B]
...
OKAY [ 0.008s]
finished. total time: 0.009s
C:\android>[B]fastboot flash system system.img[/B]
target reported max download size of 800000000 bytes
Invalid sparse file format at header magi
erasing 'system'...
OKAY [ 0.586s]
sending sparse 'system' (769417 KB)...
OKAY [ 51.696s]
writing 'system'...
(bootloader) HOSD CL#635870
(bootloader) start@1
(bootloader) system@100%
(bootloader) Update partition OK
(bootloader) end@Done
OKAY [ 23.165s]
sending sparse 'system' (781059 KB)...
OKAY [ 52.228s]
writing 'system'...
(bootloader) HOSD CL#635870
(bootloader) start@1
(bootloader) system@100%
(bootloader) Update partition OK
(bootloader) end@Done
OKAY [ 23.136s]
sending sparse 'system' (774982 KB)...
OKAY [ 51.796s]
writing 'system'...
(bootloader) HOSD CL#635870
(bootloader) start@1
(bootloader) system@100%
(bootloader) Update partition OK
(bootloader) end@Done
OKAY [ 23.455s]
sending sparse 'system' (773579 KB)...
OKAY [ 52.494s]
writing 'system'...
(bootloader) HOSD CL#635870
(bootloader) start@1
(bootloader) system@100%
(bootloader) Update partition OK
(bootloader) end@Done
OKAY [ 24.239s]
finished. total time: 302.806s

C:\android>[B]fastboot reboot-bootloader[/B]
rebooting into bootloader...
OKAY [ 0.002s]
finished. total time: 0.003s

C:\android>[B]fastboot oem rebootRUU[/B]
...
OKAY [ 0.035s]
finished. total time: 0.037s

C:\android>[B]fastboot flash zip firmware.zip[/B]
target reported max download size of 800000000 bytes
sending 'zip' (105222 KB)...
OKAY [ 7.750s]
writing 'zip'...
(bootloader) HOSD CL#635870
(bootloader) GPT is up-to-dated. [17408]
(bootloader) Perform pre-update
(bootloader) start@22
(bootloader) splash1.nb0@BYPASS
(bootloader) adsp.img@BYPASS
(bootloader) rfg_1.img@BYPASS
(bootloader) wcnss.img@BYPASS
(bootloader) sensor_hub.img@BYPASS
(bootloader) sbl1-8952-1.img@100%
(bootloader) tp_SYN3708.img@BYPASS
(bootloader) pg2fs_ship_signkey.img@BYPASS
(bootloader) apppreload.img@BYPASS
(bootloader) rpm-8952-1.img@100%
(bootloader) tz-8952-1.img@100%
(bootloader) hyp-8952-1.img@100%
(bootloader) cota.img@BYPASS
(bootloader) dsp.img@BYPASS
(bootloader) fsc.img@BYPASS
(bootloader) aboot_signed.img@100%
(bootloader) hosd_signed.img@100%
(bootloader) keymaster.img@100%
(bootloader) recovery_signed.img@BYPASS
(bootloader) boot_signed.img@BYPASS
(bootloader) cmnlib32.img@100%
(bootloader) radio.img@BYPASS
FAILED (remote: 90 hboot pre-update! please flush image again immediately )
finished. total time: 10.300s

C:\android>[B]fastboot flash zip firmware.zip[/B]
< waiting for device >
target reported max download size of 800000000 bytes
sending 'zip' (105222 KB)...
OKAY [ 7.190s]
writing 'zip'...
(bootloader) HOSD CL#688951
(bootloader) GPT is up-to-dated. [17408]
(bootloader) start@22
(bootloader) splash1.nb0@100%
(bootloader) adsp.img@100%
(bootloader) rfg_1.img@100%
(bootloader) wcnss.img@100%
(bootloader) sbl1-8952-1.img@100%
(bootloader) pg2fs_ship_signkey.img@100%
(bootloader) apppreload.img@22%
(bootloader) apppreload.img@45%
(bootloader) apppreload.img@68%
(bootloader) apppreload.img@90%
(bootloader) apppreload.img@100%
(bootloader) rpm-8952-1.img@100%
(bootloader) tz-8952-1.img@100%
(bootloader) hyp-8952-1.img@100%
(bootloader) sensor_hub.img@0%
(bootloader) cota.img@100%
(bootloader) dsp.img@100%
(bootloader) fsc.img@100%
(bootloader) aboot_signed.img@100%
(bootloader) hosd_signed.img@100%
(bootloader) keymaster.img@100%
(bootloader) sensor_hub.img@0%
(bootloader) recovery_signed.img@100%
(bootloader) boot_signed.img@100%
(bootloader) cmnlib32.img@100%
(bootloader) radio.img@100%
(bootloader) sensor_hub.img@15%
(bootloader) sensor_hub.img@30%
(bootloader) sensor_hub.img@40%
(bootloader) sensor_hub.img@55%
(bootloader) sensor_hub.img@70%
(bootloader) sensor_hub.img@85%
(bootloader) sensor_hub.img@100%
(bootloader) sensor_hub.img@100%
(bootloader) tp_SYN3708.img@100%
(bootloader) tp_SYN3708.img@100%
(bootloader) Update zip file OK
(bootloader) end@Done
OKAY [ 55.539s]
finished. total time: 62.732s

C:\android>[B]fastboot reboot-bootloader[/B]
rebooting into bootloader...
OKAY [ 0.002s]
finished. total time: 0.002s

C:\android>[B]fastboot flash recovery twrp-2.8.8.1-hiae.img[/B]
target reported max download size of 536870912 bytes
sending 'recovery' (44168 KB)...
OKAY [ 7.384s]
writing 'recovery'...
OKAY [ 0.399s]
finished. total time: 7.785s